The point is to demonstrate that if a determined killer wants to train with a type of weapon, there are systems of skills that have manifested around essentially anything that can be used to kill people and can be effectively implemented with the correct game plan and determination.

Yeah, given enough time, patience and determination you can probably train a pet monkey to kill in large numbers by expertly using a slingshot.

And how many mass murderers determined enough to invest years of specialized training and costs associated with it have we witnessed so far? Aside, of course, from 9/11 hijackers who incidentally used neither a knife nor a gun but an entirely new method.

Point is there's no available tool other than a gun that is as easily operated by an untrained individual, able to inflict the greatest amount of destruction in the shortest period of time and allows a perpetrator physical distance from his(her) victims maximizing his chances at staying alive and thus, bringing more carnage. Comparing a possible scope of damage imposed by a firearm usage to that of a blade is a specious argument. By the way, BJS agrees - there have been roughly 11,000 -12,000 firearm related murders yearly for the past decade. And only about 1000 murders by stabbing.